Bayer AG (BAYN)’s patent on the birth control pill Yaz is invalid, a U.S. appeals court said in a decision that ensures Actavis Inc. (ACT) and Novartis AG (NOVN)’s Sandoz unit can sell copies of the contraceptive. Actavis, Sandoz and Lupin Ltd. (LPC) won a ruling that the patent is invalid because it’s an obvious variation of earlier know- how, the U.S. Court of Appeals for the Federal Circuit in Washington said in an opinion posted today on its website. The court overturned a trial judge’s decision to uphold the patent, which expires in June 2014. U.S. sales of branded and generic Yaz were about $347 million in the 12 months ended Feb. 28, according to Actavis, which said in a statement today it began sales of its own version because of the court ruling.